The present invention relates to absorbent articles which are adapted to contain body exudates. More particularly, the invention pertains to pant-like disposable absorbent articles having hinged fastenings and methods of making such disposable absorbent articles.
Current disposable absorbent training pants for children going through the potty training stage have proved to be a particularly desirable and useful product. Such training pants generally include an absorbent chassis including a liquid impervious outer cover, a liquid pervious bodyside liner and an absorbent structure. The training pants further include elastic side panels that are joined to opposite side edges of the absorbent chassis. The chassis and side panels thereby form a unitary waist opening and two leg openings. Due principally to the elastic side panels, such training pants provide an exceptionally good fit to the wearer. Additional gathering means along the waist and leg openings may also be employed to further enhance fit.
Training pants are particularly suited for children who have outgrown, or believe they have outgrown, traditional diaper products. Children identify diaper products with babies, and most children do not like being identified with or as babies. Consequently, these children do not want to wear baby diapers, and instead prefer to wear training pants that look like adult underwear.
One drawback with current training pants, however, is that the interior of the pants cannot be occasionally checked for wetness without pulling the pant downward. This method of inspection can be problematic, for example, when the pant has been soiled. And while the integral side panels of current training pants are typically constructed to permit tearing in order to remove the pant, tearing the side panels is not suitable for simply inspecting the interior. Thus, it would be desirable to have a disposable absorbent article that provides the beneficial fit attributes of current training pants yet affords easier access to the interior of the pant for purposes of inspection.
In response to the above-referenced unfulfilled need in the prior art, a new disposable absorbent article and a method of making a disposable absorbent article have been discovered. The absorbent article has a pant-like appearance, which is desirable to children of toilet training age and is appealing to caregivers and to users of other ages. The absorbent article includes a fastening system that can be repeatedly fastened, unfastened and refastened. Despite the incorporation of a refastenable fastening system, the absorbent article provides the level of fit and comfort in use that has come to be associated with current training pants having elastic side panels. The fasteners of the absorbent article include xe2x80x9chinge areasxe2x80x9d that, due to their location and design, cause the fasteners to bend in conformity with the movements of the wearer""s body. The hinge areas prevent localized build up of stresses that would otherwise predispose the fastener to disengage unexpectedly.
In one embodiment, the present invention pertains to an absorbent article that defines a longitudinal axis and first and second longitudinally spaced waist regions. The absorbent article includes an absorbent chassis and a fastening system. The fastening system includes at least one first fastening component attached to the absorbent chassis and disposed in the first waist region and at least one second fastening component attached to the absorbent chassis and disposed in the second waist region. The first and second fastening components are adapted to releasably engage one another. The first fastening component has a length-to-width ratio of about 2 or greater and at least one hinge area that transversely bisects the first fastening component.
The first and second fastening components form a refastenable seam for securing the front and back waist regions together. If the training pant becomes soiled during use, the first fastening components can be disengaged from the second fastening components to easily remove the training pant from the waist of the wearer with reduced risk of undesirably soiling the clothes or legs of the wearer. The fastening components can also be easily disengaged from one another to inspect the training pant for possible soiling. Thus, the training pant is configured to be pulled on or off over the hips of the wearer such as conventional training pants and can be readily applied or removed by disengaging the fasteners similar to conventional diaper articles. Moreover, the first and second fastening components can be repositioned if necessary after the training pant has been pulled on over the legs and hips of the wearer.
A beneficial consequence of the hinged first fastening components is that the stiffness of the total length of the seam is reduced. This limits the amount of stress that can build up, which consequently reduces the likelihood that the fasteners will either buckle away from the body of the wearer or become partially disengaged from one another.
Advantageously, the location where the refastenable seam will bend during use can be controlled. Most desirably, the seam can be made to bend in areas that would otherwise give rise to fastener pop-opens. Additionally, the seam can be made to remain flat in the critical areas, such as for fit, leakage control or appearance. One common critical area is toward the lower portion of a longitudinally-oriented seam, near the leg opening of the garment. This critical area is at the maximum circumference of the body where the quadriceps insert into the hips. In this area, the side panels and chassis are under maximum stress and strain for two reasons. First, the maximum circumference puts the highest level of tension force into the elastic components of the side panels in this area of the pant. Second, the articulation of the leg also occurs in this area putting bending and compression forces into this area. This high tension and constant movement makes the lower portion of the reattachable seam prone to popping open.
The refastenable seams are formed when the first fastening components are engaged with the second fastening components. The refastenable seams are desirably relatively thin, narrow and flexible to afford the look and feel of a cloth garment. Thus, in particular embodiments, the refastenable seams have a length-to-width ratio of about 2 or greater, such as about 2 to about 25, particularly about 5 or greater, such as about 5 to about 8. The refastenable seams define a length dimension and a width dimension that is perpendicular to the length dimension. For a child of about 9 to about 15 kilograms (20-34 lbs.), for example, the length dimension is desirably from about 5 to about 13 centimeters, such as about 10 centimeters, and the width dimension is desirably from about 0.5 to about 3 centimeters, such as about 2 centimeters. Desirably although not necessarily, the length dimension is aligned generally parallel to the longitudinal axis of the absorbent article and the width dimension is aligned generally parallel to the transverse axis of the absorbent article. The term xe2x80x9cgenerally parallelxe2x80x9d as used herein refers to an angle within about 35 degrees or less of the referenced axis, and more particularly within about 20 degrees or less of the referenced axis.
In another embodiment, the present invention pertains to an absorbent article defining a longitudinal axis, first and second longitudinally spaced waist regions, and a crotch region which extends between and interconnects the first and second waist regions. The absorbent article includes an absorbent chassis and a fastening system, and the fastening system includes a pair of first fastening components attached to the absorbent chassis and disposed in the first waist region and at least one second fastening component attached to the absorbent chassis and disposed in the second waist region. The first and second fastening components are formed of mechanical fastening elements that are adapted to releasably engage one another. Moreover, each first fastening component has a length dimension, a width dimension, a length-to-width ratio of about 2 or greater, and at least one hinge area that transversely bisects the first fastening component.
The fastening components can comprise any refastenable fasteners suitable for absorbent articles, although desirably employing mechanical fastening elements rather than adhesive fastening elements. Suitable mechanical fastening elements can be provided by interlocking geometric shaped materials, such as hooks, loops, bulbs, mushrooms, arrowheads, balls on stems, male and female mating components, buckles, snaps, or the like. In particular embodiments, the fastening components comprise hook-and-loop fastening elements. One skilled in the art will recognize that the shape, density and polymer composition of the hooks and loops can be selected to obtain the desired level of securement between the fastening components and the mating fastening components. A more aggressive hook material can comprise a material with a greater average hook height, a greater percentage of directionally-aligned hooks, or a more aggressive hook shape.
The hinge areas can be formed in the fastening component material by cutting, scoring, perforating, melting such as with ultrasonics, cut and place spacing, or the like. Where a first fastening component is slit or segmented to form a hinge area, the spacing between the first fastening component segments should be kept to 15 millimeters or less, particularly 10 millimeters or less, more particularly 5 millimeter or less, and still more particularly 3 millimeters or less. The spacings create individual fastening component segments which jointly define the length and width dimensions of the fastening component.
The fastening components can include one, two, three, four or more hinge areas spaced along the length of the fastening components. Where increased flexibility of the fastening components is desired, each fastening component can even comprise 0.5 hinge areas per centimeter or more, particularly 1 hinge area per centimeter or more, more particularly 2 hinge areas per centimeter or more, such as 4 hinge areas per centimeter or more, where the number of hinge areas per centimeter is counted along the length dimension of the fastening component.
The hinge areas can be present anywhere along the length of the first fastening component. Desirably, the hinge areas are located along the length of the first fastening components where there is likely to be deformation and flexing during in use. One such area is often toward the inward end of the first fastening component, corresponding to the maximum circumference of the body where the quadriceps insert into the hips. In this area, the side panels and absorbent chassis are under maximum stress and strain. More particularly, the maximum circumference puts the highest level of tension into the side panels in this area of the pant. Also, the articulation of the leg occurs in this area thereby centering bending and compression forces in this area. This high tension and frequent movement makes the area of the refastenable seam particularly appropriate for location of the hinge areas.
Hence, in particular embodiments, each first fastening component defines an inner end edge disposed toward a leg opening of the absorbent article and an opposite outer end edge disposed toward a waist opening of the absorbent article, and at least one hinge area is offset along the length dimension of each fastening component so that it is closer to the inner end edge than the outer end edge. More particularly, the hinge area is desirably spaced from the inner end edge by about 5 to about 40 percent of the length of the fastener, particularly by about 5 to about 25 percent of the length of the fastener, and more particularly by about 5 to about 15 percent of the length of the fastener.
Thus another embodiment of the present invention pertains to a disposable absorbent pant defining a longitudinal axis, front and back longitudinally spaced waist regions, and a crotch region which extends between and interconnects the front and back waist regions. The pant includes a liquid permeable bodyside liner, a liquid impermeable outer cover bonded to the bodyside liner, and an absorbent assembly disposed between the bodyside liner and the outer cover. The pant also includes elastomeric side panels bonded to the outer cover in at least the back waist region. A pair of first fastening components are disposed on the elastomeric side panels in the back waist region, and a pair of second fastening components are disposed in the front waist region. The first and second fastening components comprise mechanical fastening elements that are adapted to releasably engage one another to define mating pairs of fasteners and form the waist and leg openings of the absorbent pant. Each of the first and second fastening components has an inner end edge disposed toward one of the leg openings, an opposite outer end edge disposed toward the waist opening, a length dimension that is generally parallel to the longitudinal axis, a width dimension, and a length-to-width ratio of about 5 or greater. At least one fastening component of each mating pair of fasteners has at least one hinge area that transversely bisects the at least one fastening component, and the hinge area is offset along the length dimension closer to the inner end edge than the outer end edge, that is, closer to the leg openings.
As noted above, the present fastening system prevents the localized build up of stresses that predispose the fastener to disengage unexpectedly. Fasteners lacking the disclosed hinge areas tend to experience areas of flexing and deformation creating concentrated stress areas. For mechanical-type fasteners, this problem is not adequately addressed by employing more aggressive fasteners, i.e., those creating higher peel strength, because such fasteners tend to be stiffer. Stiffer fastening material exacerbates rather than ameliorates the problem because stiffer materials increase the amount of stresses that build up when the fastener is flexed. Moreover, aggressive fasteners interfere with the additional objective of making the fastener easy to remove, particularly in the context of training pants where the user is a child.
The disclosed absorbent articles are adapted to be worn adjacent to the body of a wearer to absorb and contain various exudates discharged from the body. The absorbent articles are desirably pre-fastened to provide a pant-like product for the user. The product can then be pulled on like a conventional training pant, and subsequently checked or removed with the ease of a diaper-like product. Moreover, the product can be applied like a diaper rather than like a pant. Supplemental releasable fastening means such as frangible point bonds can be employed to maintain the absorbent article in a pant configuration until the user intentionally disengages the fasteners.
The fastening system allows for easy inspection of the interior of the pant-like product. If necessary, the fastening system also allows the pant to be removed quickly and easily. This is particularly beneficial when the pant contains messy excrement. If desired, the caregiver can completely remove the pant-like product and replace it with a new one without having to remove the child""s shoes and clothing. The present fastening system can be used with a wide variety of absorbent products, including training pants, diapers, incontinence garments, or other garments using mechanical or adhesive fasteners.
The present invention also pertains to a method of making an absorbent article that defines a longitudinal axis, a transverse axis, a first waist region, an opposite second waist region, and a crotch region which extends between and interconnects the first and second waist regions. In one embodiment, a method of making an absorbent article comprises: providing an absorbent chassis; attaching at least one first fastening component to the absorbent chassis in the first waist region; and attaching at least one second fastening component to the absorbent chassis in the second waist region; wherein the first and second fastening components comprise mechanical fastening elements that are adapted to releasably engage one another and the first fastening component comprises at least one hinge area that transversely bisects the first fastening component.
A more detailed description of the construction and design of one form of training pant can be found in U.S. Pat. No. 4,940,464 issued Jul. 10, 1990 to Van Gompel et al., which is incorporated herein by reference. The Van Gompel et al. patent describes various materials of which the training pant can be made, and a method of constructing a training pant.
Within the context of this specification, each term or phrase below will include the following meaning or meanings.
xe2x80x9cBondedxe2x80x9d refers to the joining, adhering, connecting, attaching, or the like, of two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements.
xe2x80x9cComprisingxe2x80x9d is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.
xe2x80x9cConnectedxe2x80x9d refers to the joining, adhering, bonding, attaching, or the like, of two elements. Two elements will be considered to be connected together when they are connected directly to one another or indirectly to one another, such as when each is directly connected to intermediate elements.
xe2x80x9cDisposablexe2x80x9d refers to articles which are designed to be discarded after a limited use rather than being laundered or otherwise restored for reuse.
xe2x80x9cDisposed,xe2x80x9d xe2x80x9cdisposed on,xe2x80x9d and variations thereof are intended to mean that one element can be integral with another element, or that one element can be a separate structure bonded to or placed with or placed near another element.
xe2x80x9cElastic,xe2x80x9d xe2x80x9celasticizedxe2x80x9d and xe2x80x9celasticityxe2x80x9d mean that property of a material or composite by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation.
xe2x80x9cElastomericxe2x80x9d refers to a material or composite which can be elongated by at least 25 percent of its relaxed length and which will recover, upon release of the applied force, at least 10 percent of its elongation. It is generally preferred that the elastomeric material or composite be capable of being elongated by at least 100 percent, more preferably by at least 300 percent, of its relaxed length and recover, upon release of an applied force, at least 50 percent of its elongation.
xe2x80x9cFabricsxe2x80x9d is used to refer to all of the woven, knitted and nonwoven fibrous webs.
xe2x80x9cFlexiblexe2x80x9d refers to materials which are compliant and which will readily conform to the general shape and contours of the wearer""s body.
xe2x80x9cForcexe2x80x9d includes a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move. Force is expressed in grams per unit area.
xe2x80x9cGraphicxe2x80x9d refers to any design, pattern, or the like that is visible on an absorbent article.
xe2x80x9cHydrophilicxe2x80x9d describes fibers or the surfaces of fibers which are wetted by the aqueous liquids in contact with the fibers. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular fiber materials or blends of fiber materials can be provided by a Cahn SFA-222 Surface Force Analyzer System, or a substantially equivalent system. When measured with this system, fibers having contact angles less than 90xc2x0 are designated xe2x80x9cwettablexe2x80x9d or hydrophilic, while fibers having contact angles greater than 90xc2x0 are designated xe2x80x9cnonwettablexe2x80x9d or hydrophobic.
xe2x80x9cIntegralxe2x80x9d is used to refer to various portions of a single unitary element rather than separate structures bonded to or placed with or placed near one another.
xe2x80x9cInwardxe2x80x9d and xe2x80x9coutwardxe2x80x9d refer to positions relative to the center of an absorbent article, and particularly transversely and/or longitudinally closer to or away from the longitudinal and transverse center of the absorbent article.
xe2x80x9cLayerxe2x80x9d when used in the singular can have the dual meaning of a single element or a plurality of elements.
xe2x80x9cLiquid impermeablexe2x80x9d, when used in describing a layer or multi-layer laminate, means that a liquid, such as urine, will not pass through the layer or laminate, under ordinary use conditions, in a direction generally perpendicular to the plane of the layer or laminate at the point of liquid contact. Liquid, or urine, may spread or be transported parallel to the plane of the liquid impermeable layer or laminate, but this is not considered to be within the meaning of xe2x80x9cliquid impermeablexe2x80x9d when used herein.
xe2x80x9cLongitudinalxe2x80x9d and xe2x80x9ctransversexe2x80x9d have their customary meaning, as indicated by the longitudinal and transverse axes depicted in FIGS. 2 and 3. The longitudinal axis lies in the plane of the article and is generally parallel to a vertical plane that bisects a standing wearer into left and right body halves when the article is worn. The transverse axis lies in the plane of the article generally perpendicular to the longitudinal axis. The article as illustrated is longer in the longitudinal direction than in the transverse direction.
xe2x80x9cMemberxe2x80x9d when used in the singular can have the dual meaning of a single element or a plurality of elements.
xe2x80x9cNonwoven webxe2x80x9d means a web of material which is formed without the aid of a textile weaving or knitting process.
xe2x80x9cOperatively joined,xe2x80x9d with reference to the attachment of an elastic member to another element, means that the elastic member when attached to or connected to the element, or treated with heat or chemicals, by stretching, or the like, gives the element elastic properties; and with reference to the attachment of a non-elastic member to another element, means that the member and element can be attached in any suitable manner that permits or allows them to perform the intended or described function of the joinder. The joining, attaching, connecting or the like can be either directly, such as joining either member directly to an element, or can be indirectly by means of another member disposed between the first member and the first element.
xe2x80x9cOuter cover graphicxe2x80x9d refers to a graphic that is directly visible upon inspection of the exterior surface of a garment, and for a refastenable garment is in reference to inspection of the exterior surface of the garment when the fastening system is engaged as it would be during use.
xe2x80x9cPermanently bondedxe2x80x9d refers to the joining, adhering, connecting, attaching, or the like, of two elements of an absorbent garment such that the elements tend to be and remain bonded during normal use conditions of the absorbent garment.
xe2x80x9cRefastenablexe2x80x9d refers to the property of two elements being capable of releasable attachment, separation, and subsequent releasable reattachment without substantial permanent deformation or rupture.
xe2x80x9cReleasably attached,xe2x80x9d xe2x80x9creleasably engagedxe2x80x9d and variations thereof refer to two elements being connected or connectable such that the elements tend to remain connected absent a separation force applied to one or both of the elements, and the elements being capable of separation without substantial permanent deformation or rupture. The required separation force is typically beyond that encountered while wearing the absorbent garment.
xe2x80x9cRupturexe2x80x9d means the breaking or tearing apart of a material; in tensile testing, the term refers to the total separation of a material into two parts either all at once or in stages, or the development of a hole in some materials.
xe2x80x9cStretch bondedxe2x80x9d refers to an elastic member being bonded to another member while the elastic member is extended at least about 25 percent of its relaxed length. Desirably, the term xe2x80x9cstretch bondedxe2x80x9d refers to the situation wherein the elastic member is extended at least about 100 percent, and more desirably at least about 300 percent, of its relaxed length when it is bonded to the other member.
xe2x80x9cStretch bonded laminatexe2x80x9d refers to a composite material having at least two layers in which one layer is a gatherable layer and the other layer is an elastic layer. The layers are joined together when the elastic layer is in an extended condition so that upon relaxing the layers, the gatherable layer is gathered.
xe2x80x9cSurfacexe2x80x9d includes any layer, film, woven, nonwoven, laminate, composite, or the like, whether pervious or impervious to air, gas, and/or liquids.
xe2x80x9cTensionxe2x80x9d includes a uniaxial force tending to cause the extension of a body or the balancing force within that body resisting the extension.
xe2x80x9cThermoplasticxe2x80x9d describes a material that softens when exposed to heat and which substantially returns to a nonsoftened condition when cooled to room temperature.
xe2x80x9cTransversely bisectxe2x80x9d refers to a hinge or hinge area extending laterally across a fastening component so that the fastening component will bend in response to body movements about an axis that is generally perpendicular to the longitudinal axis of the fastening component.
These terms may be defined with additional language in the remaining portions of the specification.